The present invention provides a novel thermoplastic composition of matter obtained by plasticizing scraps of leather (as herein defined) under the action of elevated pressure and temperature. The invention further provides a process for the production of said novel composition of matter.
The term "leather" as used herein is meant to refer to both tanned and untanned natural leather, skins or hides of all kinds of animal origin.
One of the objects of the present invention is to make use of leather scraps, comparatively large amounts of which are the necessary by-products of the leather products industry, especially the shoe industry. Such leather scrap is available in various forms, e.g. flat pieces of various shapes, narrow strips, grains and powder. Despite the comparatively high price of natural leather, hardly any significant attempts have hitherto been made to exploit these leather scraps, even less to convert it to industrially useful materials.
It has now been surprisingly found in accordance with the present invention that when leather scrap is subjected to the action of high pressure and moderately elevated temperatures in a closed die for comparatively short periods, there is obtained a novel and useful composition of matter having advantageous physical properties which render it useful in various technical and industrial applications.
The invention thus provides, in one aspect thereof, a novel thermoplastic composition of matter consisting substantially of leather (as herein defined) which has been converted to a solid thermoplastic mass by the action of a pressure from about 200 to about 900 bar at a temperature from about 50.degree. to about 250.degree. C. in a closed die, said composition of matter optionally including additives and/or fillers.
In another aspect, the invention provides a process for producing the above-described novel composition of matter, which comprises subjecting leather (as herein defined), optionally admixed with one or more additives and/or fillers, to the action of a pressure from about 200 to about 900 bar, at a temperature from about 50.degree. to about 250.degree. C. in a closed die for a time of at least about 30 seconds.